As one conventional example of a refrigeration apparatus which performs a multistage compression refrigeration cycle by using a refrigerant that operates in a supercritical range, Japanese Laid-open Patent Application No. 2007-232263 discloses an air-conditioning apparatus performs a two-stage-compression refrigeration cycle by using carbon dioxide as a refrigerant. This air-conditioning apparatus has primarily a compressor having two compression elements connected in series, an outdoor heat exchanger as a heat source-side heat exchanger, an expansion valve, and an indoor heat exchanger.